1. Field of the Invention
This invention is directed to a coating composition, in particular, to a multiple component coating composition particularly useful for automotive refinish applications.
2. Description of the Prior Art
In the refinishing of automobiles or trucks, after they have been damaged or in the repainting of automobiles and trucks or parts thereof, the refinish paint or coating composition that is used is required to cure at ambient temperatures or slightly elevated curing temperature of, for example, 40 to 80° C. Higher baking temperatures that are used in OEM (original equipment manufacture) can not be used since the interior and the many plastic parts used in automobiles and trucks would be damaged. Typical refinish coating compositions utilize multiple components. For example, a typical base coat for a conventional base coat/clear coat finish or a colored mono coat utilize a tint containing pigments, a binder containing film forming constituents, a reducer which is a solvent mixture to reduce the viscosity of the composition to a spray viscosity and a crosslinking component which typically is a polyisocyanate. A typical clear coat used for refinishing or repainting contains all of the above components except for the tint.
It would be desirable to simplify the formulation of these compositions, for example, by reducing the number of components used in the formulation thereof. Such an attempt has been made by blending the crosslinking component, a polyisocyanate, with the reducer. But typical polyisocyanate crosslinking agents that are conventionally used in these refinish coating compositions, such as, hexamethylene diisocyanate, trimers of hexamethylene diisocyanate, isophorone diisocyanate and the like when mixed with typical reducing solvents at low levels of polyisocyanate concentration of 30 percent and less are not stable and typically have a shelf life of less than one week under ambient temperature conditions.
It would be desirable to develop a multiple component coating composition that utilizes a stable polyisocyanate solution that has a low concentration of polyisocyanate that can be used to formulate primer compositions, base coating compositions, pigmented mono-coat compositions, and clear coat compositions that are useful for refinishing and repainting automobile bodies, truck bodies and parts thereof.